Self-opening die.



No. 740.016 PATENTED SEPT. 29, 1903..

L. A. HOWE.

SELF OPENING DIE.

APPLICATION FILED JUNE 15, 1903.

N0 MODEL.

Patented September 29, 1903.

' .UNITED STATES PATENT OFFICE.

LEWIS A. HOWE, OF BARRE, MASSACHUSETTS, ASSIGNOR on ONE-HALF To HARDINGALLEN, OF BARRE, MASSACHUSETTS.

SELF-OPENING DIE.

SPECIFICATION forming part of Letters Patent No. 740,016, datedSeptember 29, 1903.

' Application filed June 15, 1903. Serial No. 161.446. (No model.)

' To all whom it may concern.-

Be it known that I, LEWIS A. HOWE, a citi zen of the United States,residing at Barre, in the county of Worcester and-State ofMassachusetts, have invented a new and useful Self-Opening Die, of whichthe following is a specification. r

This in vention relates to that class of threadcutting dies in which thethreading-jaws are separated to permit the withdrawal of the work.

The especial object of this invention is to provide a setting mechanismfor a self-opening die which will set the threading-jaws to twodifierent positions, the more, open position being used for aroughing-out out, while the second position of the jaws is used for thefinished chip or cutting of threadsto exactly the desired size. I

This invention is shown as an improvement upon the threading-dieshown,described, and

claimed in the application for patent. filed by me November 28, 1902,Serial No. 133,140.

In the accompanying drawings, Figure l is a side View, partially brokenaway, of a threading-die constructed according to this invention. Fig. 2is a front View thereof, partially broken away, showing thethreadingjaws in their open or separated position. Fig. 3 is a frontview showing the threading-jaws in their partly-closed or roughing-outposition. Fig/iris a similar view showing the threading-jaws in positionfor cutting the finished thread, and Fig. 5 is a detail view of the pinfor setting the movable threading-die to its roughing-out orthread-finishing position. Two forms of dies are now commonly em.-ployed for cutting screw-threads. 'For ordinary purposes-for example, in.an ordinary die-stocka solid or fixed die may be employed, which has tobe run back over the threads when work is being removed therefrom.Reversal of a die to run the Same back over the threads which have beenformed or cut thereby is objectionable, for the reason that the backtravel of the die injures and mars the threads and at the same timedolls and quickly wears out the threading-teeth.

For better classes of work self-opening dies are now employed in whichthe threadingteeth are moved away from the work when a thread has beencompleted, so that the work can then be withdrawn without running thedie back over the threads.

In my prior application for patent, before referred to, I have shown,described, and claimed a self-opening die comprising a baseplate withlaterally-separable members which are movable toward and away from thebasev plate, with pins extending from the base plate to engage socketsin the laterally-separable members to hold them in operative position,but permitting them to separate when moved away from the base-plate andofl of the ends of the pins.

In the construction shown in my aforesaid application for patent thepins are rigidly secured in the base-plate.

Theespecial object of my present invention is to provide simple andefficient means for adjusting one or both of these holdingpins in a dieof the class described, so that the threading-teeth may be set for aroughing chip to cut a thread of approximately the desired diameter andmay afterward be set together to finish the thread exactly the rightsize. To accomplish this result, .in practice I have found that this canbe conveniently done by pivotally mounting the movable pin in the baseplate and providing the pin at its end with an eccentric or o'fisetportion for engaging one of the separable members, and by means of thisconstruction when the pin is turned to one position one of the separablemembers will be moved slightly away from the work in position for aroughing-out cut, and when the pin is turned to another position theseparable members willv move to their closed position to cut threads ofthe accurate size.

Referring to the drawings for a detail description of a die embodyingthis invention as illustrated herein, the die comprises a hollow spindleor shaft 10. Carried by the spindle 10 is a base-plate 11. Driven orotherwise fastened in the base-plate 11 is a stationary holding-pin 12,and pivoted in the base-plate 11 is a movable holding-pin 4.0. Adjustably mounted on the pins 12 and 40 is a guide-piece 13. Theguide-piece 13 is movable upon its pins toward and away from thebase-plate, the limit of its forward movement being regulated by astop-screw 14.

As shown most clearly in Fig. 2, the guidepiece 13 has a transverse wayor slot out therein, and fitting into this slot are separable dieholdingpieces 15, which are provided with extending flanges holding them inplace in their slot.

Adjustably mounted in the separable pieces 15 are the two-part dies.Each of these twopart dies is fastened in place in its holder 15 byfastening-screws 19, and the dies are set to position by end screws 20.

The separable die-holders 15 are normally separated by a spring.

As herein illustrated, a screw 21 is threaded into each of thedie-holders 15. The screws 21 extend out through slots in the guidepiece13, and mounted on the screws 21 are telescoping sections or tubes 22,containing a spring 23.

Any ordinary means may be employed for regulating the length of threadcut by the die. For example, an adjustable pencil or spindle 25 may befitted within the hollow spindle 10.

Referring now to the pivoted pin 40, it will be seen that this pin 40,as illustrated most clearly in Fig. 5, is provided at one end with aneccentric portion which engages one of the die-holders 15, and securedon the other end of the pin 40 is an operating-handle 42.

Considering now the operation of the selfopening die in the actual workof cutting a screw-tn read upon a rod or bolt, the parts of the die arefirst set to the position illustrated in Fig. 3, and either the work orthe die itself, as the case may be, is turned, and after the work hasentered between the cuttingjaws of the die the end of the work willadvance into the die until it engages the end of the adjustable stop orred. This will cut or rough out a screw-rod slightly larger in diameterthan the finished thread of desired size. When the end of the workstrikes the stop, the laterally separable members will be pulled offfrom the ends of the pins and the die will be opened to the positionillustrated in Fig. 1. The die is then again closed, the handle 42 isturned to the position indicated by dotted lines in Fig. 4, and by againrunning the die over the work a finished thread of exactly the desiredsize will be obtained.

I am aware that numerous changes maybe made in practicing my inventionby those who are skilled in the art-that is to say, numerous other meansmay be devised for setting and adjusting one of the holding-pins insteadof using the pivotal eccentric arrangement I have herein described. Itis also to be understood that, if desired, both holding-pins may be madeadjustable, although in practice I have found that sufficiently accurateresults may be obtained by simply setting or adjusting one of such pins.1 do not wish, therefore, to be limited to the special construction Ihave herein shown and described; but

What I do claim, and desire to secure by Letters Patent of the UnitedStates, is-

1. In a self-opening die, the combination ofa base-plate or support,laterally-separable members which are movable toward and away from thebase-plate, pins extending from the base-plate to engage sockets in thelaterallyseparable members to hold them in place, but permitting them toseparate when moved away from the base-plate and off the ends of thepins, and means for adjusting one of the pins to enable the die to makea roughing cut before cutting a screw-thread of the desired diameter.

2. In a self-opening die, the combination of a base-plate or support,pins extending from the base-plate, aguide-piece mounted on the pins andmovable thereon toward and away from the base-plate, andlaterally-separable members mounted in the guide-piece and havingsockets to be engaged by the ends of the pins when the guide-piece is inits normal position, but which are disengaged from the ends of the pinswhen the guide-piece is moved away from the base-plate, and means foradjusting one of said pins.

3. In a self-opening die, the combination of a base-plate or support,pins extending therefrom, a guide-piece mounted on the pins and movablethereon toward and away from the base-plate, laterally-separable memberswith socketsfor receiving the ends of the pins mounted in theguide'piece, dies adjustably mounted in the laterally-separable members,and means for adjusting one of the pins to set the die for roughing orfinishing cuts as desired. I

4. In a self-opening die, the combination of a base-plate or support,laterally-separable members movable toward and away from the base-plate,and pins extending from the baseplate to engage sockets in thelaterally-separable members, one of said pins being pivoted in thebase-plate and having a handle for turning the same, and having the endthereof which engages one of the separable members eccentric withrespect to its pivot, whereby the die may be set for roughing orfinished cuts, as desired.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

LEYVIS A. HOWE.

\Vitncsses:

JAMES CRANE, C. II. FOLLANSBY.

